Chemical synthesis comprising heat treatment by intrmittent dielectric heating combined with a recycling system

ABSTRACT

This invention relates to the design of a process by intermittent dielectric heating combined with a recycling system. This process consists in subjecting reagents to electromagnetic waves selected in the frequencies ranging between 300 GHz and 3 MHz intermittently using a recycling system. This process enables the treatment of oils that are hardly absorbent as well as great investment savings. This process enables operation on different scales, whether in laboratories, on a semi-industrial or industrial scale, without forfeiting the advantages of continuous dielectric heating.

BACKGROUND OF THE INVENTION

Regardless of the complexity of the molecule to be manufactured,chemists always try to find a way to reduce the reaction time and thenumber of steps required for synthesizing a molecule because of aconstant concern regarding costs and profitability.

Many studies have been conducted for the purpose of controlling thevarious parameters capable of influencing the unfolding and speed of areaction. Additives, such as solvents, catalysts, have been widely used.Although these compounds stimulate the reaction medium, they aresometimes toxic to man and the environment, and they require expensivepost-treatments such as neutralization, washing, drying, filtration.

Today, the trend is toward manufacturing processes that are simple, lowin cost, and respectful of man and his environment.

Some physical processes have been tested: the use of ultrasounds, highfrequencies, and recently, microwaves.

The various tests conducted using dielectric heating, that is to say,heating under microwave frequencies or high frequencies, have shown thepotential value of this new technology: indeed, dielectric heatingpermits considerable time and energy savings, combined with lowerinvestment costs; the reactions no longer require the use of any solventor catalyst; burn-up and unwanted reactions are avoided.

Although today there are available many types of high-frequency andmicrowave applicators, they are all nonetheless configured in such a waythat the reaction medium is continuously exposed to electromagneticwaves in order to be able to benefit from the advantages inherent inthis new technology. The amount of material processed in this manner islimited, because it depends on the dimensions of the waveguides that arethemselves standardized.

SUMMARY OF THE INVENTION

The applicant has discovered a new heat treatment process involved in achemical synthesis: namely, intermittent dielectric heating combinedwith a recycling system. The reagents are subjected to electromagneticwaves on an intermittent basis using a recycling system. Theelectromagnetic waves are selected among the frequencies ranging from300 GHz to 3 MHz.

This process is original and low in cost. Additionally, this processenables operation on different scales, whether in laboratories, on asemi-industrial or industrial scale, without forfeiting the advantagesof continuous dielectric heating.

Applications:

The invention makes it possible to carry out efficient and rapid heattreatments on different scales, whether in laboratories, on asemi-industrial or on industrial scale.

This invention relates to all “heat applications,” that is to say, thechemical syntheses involving a heat treatment and featuring a solereagent, or a mixture of reagents, in variable proportions, with orwithout catalysts, with or without process gas.

As “heat applications,” we can cite, as non-limitative examples, suchreactions as esterification, transesterification, epoxydation,sulphatation, phosphitation, hydrogenation, peroxydation, isomerization,dehydration, quaternization, amidation, polymerization,polycondensation, and all the common treatments such as decolorizing,deodorizing, and the other systems for eliminating volatile compounds.

The invention in fact applies very specifically to all “lipochemistry”reactions.

This innovative technique permits, for example, manufacturing polymersof unsaturated fatty acids, esters of unsaturated fatty acids,unsaturated hydrocarbons or derivatives of these products usingintermittent dielectric heating under microwaves. In this connection,the applicant has filed a Patent Application FR 98 13770 and a PatentApplication PCT WO 00/26265 (PCT/FR 99/02646).

Prior Art:

The field of this invention relates to the use of microwave (MW) or highfrequency (HF) electromagnetic waves for any heat treatment.

The MW and HF Frequencies

The MW microwave frequencies are comprised between about 300 MHz andabout 30 GHz, preferably at 915 MHz (authorized frequency with atolerance of 1.4%) or at 2.45 GHz (authorized frequency with a toleranceof 2%).

The HF high frequencies are comprised between about 3 MHz and about 300MHz, preferably at 13.56 MHz (authorized frequency with a tolerance of0.05%) or at 27.12 MHz (authorized frequency with a tolerance of 0.6%).

Absorbed Power

The Absorbed Power (AP) is a dependent variable of the Incident Power(IP) and of system losses.

For a product that hardly absorbs electromagnetic waves, and for a givenIncident Power (IP), the Absorbed Power (AP) decreases and the lossesincrease, in particular those losses due to static electricity.

Indeed:IP=AP+lossesWherein:IP=Incident Power in WattsAP=Absorbed Power in WattsLosses=heat losses+static electricity

The Absorbed Power (in Watts) by a material under HF or MW treatment isexpressed by the following formula:AP=kfε″E ² Vwith:AP: Absorbed Power in WattsE: electric field created inside the material in V/cmf: frequency of waveK: constant (M.K.S.A)=5.56.10⁻¹³V: volume of material in cm³ε″: material loss factor=ε′tang δε′: actual relative permittivity of the material=ε₀*ε_(τ)∈ε₀: permittivity of vacuumε_(R): dielectric constanttang δ: angle of lossesε′ translates the ability of a material to orient itself in the field,and tang δ its ability to release heat.

Note: For air or vacuum, ε′=1 (lowest value for ε′) and tang δ=0, i.e.,ε″=0.

Type of Energy Applicators

The type of energy applicator selected depends on the technology used(high frequencies or microwaves), the dimensional characteristics of theproduct to be treated and its mode of treatment.

As regards high frequency applicators, these essentially consist in:

-   -   applicators of the capacitive type formed by two condenser        armatures between which the generator's high-frequency voltage        is applied. They are used for the heat treatment of materials        whose volume constitutes a parallelepiped, one side of which is        sufficiently thick (>10 mm).    -   applicators with rods for planar materials. These applicators        are made up of tubular or rod-shaped electrodes. They are used        for the heat treatment of materials whose volume constitutes a        parallelepiped, one side of which is insufficiently thick (<10        mm).    -   applicators for filiform materials, formed by loops.

For the microwave applicators, we can cite:

-   -   localized-field applicators: singlemode cavity    -   diffuse-field applicators: multimode cavity    -   near-field applicators: guide with radiating antennas

Among these microwave applicators, there are available on the market forexample:

-   -   the “synthewave 402” and the “synthewave 1000” that are made up        of 1 ml to 100 ml or 600 ml reactors    -   the “Discover” with 1 ml to 125 ml reactors    -   the “Ethos MR” with a capacity of less than 400 ml

Risks of Electrical Breakdown or Electric Arcs

The Applicant has filed a Patent Application FR No 0108906 concerning animproved apparatus for carrying out dielectric heating. In said patent,the invention relates to a new shape or geometry of a chimney, inparticular a chimney with a conical shape or geometry, which permitsheating any type of product under microwave frequencies or highfrequencies, in statics or dynamics with a sizeable power densitywithout any risk of electric arcs or electrical breakdown.

Any person skilled in the art may refer to said patent application forfurther details. For his/her convenience, a summary thereof is providedhereinbelow.

-   -   In the case of hardly absorbent molecules, the choice of        applicators is complicated. The applicator in fact has to        transmit a great deal of electromagnetic energy to the product        in order to be able to provide heat while avoiding electric        arcs.    -   Heating under microwave frequencies is preferable to heating        under high frequencies for which the risk of electrical        breakdown is greater.    -   The “singlemode” system (localized field) which is formed by        singlemode cavities resonating at the transmission frequency        according to a radiation in the direction of the guide is        preferred to the “multimode” (diffuse field). The singlemode        system avoids a non-homogeneous distribution of the electric        field and the presence of hot points. Likewise, this type of        reactor creates stability in the products exposed.    -   The singlemode applicator outfitted with the usual cylindrical        chimneys, which is the most suitable one of all common        applicators with hardly absorbent molecules, does not permit        working with a high density of power without running the risk of        electrical breakdown.    -   Nonetheless, the introducing into the reaction medium of some        polar compounds such as water, so as to play the role of        intermediary in energy transfer and thus reduce the density of        power needed, is still not satisfactory. Unwanted side reactions        can take place, making supplemental treatments such as        neutralization, washing, drying or filtration necessary to        purify the product at the end of the reaction.    -   One alternative to mitigate the problems related to the hardly        absorbent compounds is to eliminate the static electricity as it        forms on the outer wall of the reactor. In order to eliminate        the static electricity, one must either make for a good        ventilation using humid air or some other gas that is comparable        from the standpoint of its dielectric constants (for example:        sulfur hexafluoride SF6 under 1 bar) (1st solution), or adapt        the shapes of the chimneys so as to aerate them (2nd solution).        The first solution is not attractive due to the complexity of        equipment, safety issues, and cost reasons.    -   The applicant has discovered a new chimney shape or geometry, in        particular a conical chimney, that makes it possible to heat any        type of products under microwave frequencies or high        frequencies, in statics or in dynamics, with a sizeable power        density without any risk of electric arcs or electrical        breakdown.        Description of the Invention

The applicant has discovered a new heat treatment process that consistsof submitting the reagent, either alone or in a mixture, toelectromagnetic waves in an intermittent manner, with the help of arecycling system.

The electromagnetic waves are selected in the frequencies rangingbetween 300 GHz and 3 MHz.

This process retains the advantages of continuous dielectric heatingwhile increasing production capacity.

Description of the Equipment

The intermittent heating process is simple and low-cost. It consists of:

-   -   pumps    -   reactors subjected to the electromagnetic field    -   a dielectric system: chimney applicators, generator waveguides,        iris, shortcircuit piston, cooling systems    -   buffer reactors    -   tanks    -   a gas circuit, preferably for an inert gas such as nitrogen    -   condensers    -   measuring devices        The Pumps

The pump(s) is (are) of the variable-flow type.

It can be a feeder dosing pump and/or a recycling pump and/or a vacuumpump. The outflow of the recycling pump influences the time required fora molecule to transit under the waves.

The pumps can be selected, for purposes of indication, from among vanepumps or piston pumps.

Reactors subjected to the Electromagnetic Field

The reactors subjected to the electromagnetic field do not absorb thewaves (pyrex, quartz, etc.).

They are typically cylindrical in shape.

They are positioned inside applicators.

Dielectric system: Chimney Applicators, Generator Waveguides, Iris,Shortcircuit Piston, Cooling Systems

The applicators are formed by singlemode cavities that resonate at thetransmission frequency according to a radiation in the direction of thewaveguide.

The chimneys prevent wave leakage to the outside of the waveguide. Theyare preferably of a conical cylindrical shape, as indicated inApplication FR No 0108906 filed by this Applicant for limiting thepresence of electric arcs.

The waveguide(s) carries/carry the electromagnetic waves. Each waveguidecan be subdivided into two—and only two—waveguides.

The generators used are microwave or high-frequency generators.

The microwave (MW) frequencies range from about 300 MHz to about 30 GHz,preferably standing at 915 MHz (authorized frequency with a tolerance of1.4%) or at 2.45 GHz (authorized frequency with a tolerance of 2%).

The high frequencies (HF) range from about 3 MHz to about 300 MHz,preferably standing at 13.56 MHz (authorized frequency with a toleranceof 0.05%) or at 27.12 MHz (authorized frequency with a tolerance of0.6%).

The generators are outfitted with a safety feature that allows theincident waves to pass through and that diverts the reflected waves to awater load in which the waves are absorbed.

These generators also require the use of iris, of a shortcircuit pistonin order to decrease the reflected power and to promote absorption ofthe generator-transmitted power by the reaction mixture.

The system is outfitted with cooling systems in order to avoid anyoverheating.

The Buffer Reactors

The buffer reactors permit treating a larger amount of reaction mixture.

The Tanks

The system is outfitted with one or several feeder tank(s), receivertank(s), filtration tank(s).

The Gas Circuits

The heat treatments are carried out under a normal atmosphere, or anoxygen-rich atmosphere or, preferably, an inert atmosphere.

The Measuring Devices

The system is outfitted with measuring devices such as manometers,thermocouples, flowmeters.

This process can be used in dynamics or in continuum.

Principle of Intermittent Heating

The entire reaction volume is not continuously exposed to the waves;however, all molecules of the reaction mixture are intermittentlysubjected to the field.

Various configurations may be considered for carrying out anintermittent dielectric heating.

The first configuration consists in subjecting several reactors to theelectromagnetic waves. See FIG. 1.

The second configuration consists in using several energy applicators ona single reactor. See FIG. 2.

The number of applicators depends on the desired working temperature, onthe amount of product to be treated, on the reaction temperature risetime, on the dielectric constants of the reagents.

Any person skilled in the art will understand that other configurationsare possible besides these two and that the invention relates to allother intermediate positions.

Furthermore, the applicant has discovered an original system consistingin circulating the reaction mixture in a loop, thus reducing investmentcosts for an equivalent production capacity. Without this recyclingsystem, it would indeed be necessary to use a large-size reactor and amultitude of applicators in order to succeed in heating the same amountof products and to achieve the desired result, which would entailenormous costs.

See FIG. 3.

The intermittent dielectric heating combined with a recycling systemmakes it possible to increase the production capacities, which arelimited under the continuous dielectric heating system, represented inFIG. 4 or FIG. 3 if the applicators cover the entire volume to betreated.

This process can be used in dynamics or in continuum.

According to this configuration, the entire reaction volume is notcontinuously exposed to the waves; however, all molecules of thereaction mixture are intermittently subjected to the field.

It should be noted that, according to this principle, the inventionlogically should not have functioned, that is to say, it shouldlogically not have yielded any good results. As a matter of fact, amolecule will only be subjected to the electromagnetic waves for afraction of its circulation time, for example, 1 sec every 10 sec. Anyperson skilled in the art understands that this should have producedeither very poor results (inefficient process) or zero results. Yet,surprisingly we obtain on the contrary very good results (seehereinbelow) accompanied by the major advantages also mentioned herein.

Volume Exposed to the Electromagnetic Field

The volume exposed to the electromagnetic field is calculated accordingto the formula below:V(exposed to the field)=π*R ² *Hwherein:

R=radius of reactor exposed to the field

H=height of reactor exposed to the field

Parameter H:

The height of the reactor exposed to the field typically corresponds tothat of the waveguide in order to permit treating the maximum amount ofmaterial all at once.

Let's take the case of heat treatments under singlemode microwave, at2450 MHz. The height of the waveguide in Mode TE 0.1 (TransverseElectric) is equal to 45 mm. The fundamental mode of excitation TE 0.1makes it possible for the wave to propagate as a single arch, contraryto Mode TE 0.2 which presents two field maxima, yielding a lesshomogenous heating.

Let's take the case of heat treatments under singlemode microwave, at915 Hz. In that case, the height of the waveguide is equal to 124 mm.

Parameter R

Typically, the reactor is cylindrical in shape. Its diameter may notexceed the width of the waveguide.

In the case of singlemode microwave applicators, under 2450 MHz, therecommended waveguide width in order to remain in Mode TE 0.1(Transverse Electric) ranges from about 70 to 100 mm, standing morespecifically at 90 mm.

In the case of the singlemode microwave applicators, under 915 MHz, therecommended waveguide width in order to remain in Mode TE 0.1(Transverse Electric) stands at about 250 mm.

Advantages of the Intermittent Dielectric Heating

Contrary to the common dielectric systems this invention surprisinglypermits heating volumes of materials on an industrial scale whilekeeping the process low-cost. Therefore, the Applicant has devised aprocess involving intermittent dielectric heating combined with arecycling system.

The Applicant demonstrates, by this invention that the reagents benefitfrom the advantages inherent to the electromagnetic wave technologywithout being continuously exposed to the field. Indeed, the benefits ofthe dielectric heating are preserved:

-   -   1. the reaction time is significantly reduced;    -   2. the reaction is carried out in a single step    -   3. non-use of solvent    -   4. energy savings (because the times are significantly shorter)    -   5. absence of burn-up and side reactions.        Reagents:

For this invention, the reagent(s) can be selected from among theproducts that are hardly absorbent of electromagnetic waves or theproducts that are highly absorbent of said electromagnetic waves, or amixture of both, which may or may not be enhanced by one or severalhardly or highly absorbent catalysts or additives and/or process gases.

Vegetable Oils

As vegetable oils, we may mention, among others, rapeseed oil, sunfloweroil, peanut oil, olive oil, walnut oil, corn oil, soy oil, linseed oil,safflower oil, apricot kernel oil, sweet almond oil, hemp oil, grapeseedoil, copra oil, palm oil, cottonseed oil, Babassu oil, jojoba oil,sesame oil, argan oil, milk-thistle oil, gourdseed oil, raspberry oil,Karanja oil, neem oil, poppyseed oil, Brazilnut oil, castor oil,dehydrated castor oil, hazelnut oil, wheat germ oil, borage oil,oenothera oil, Tung oil, or tall oil.

Animal Fats or Oils

As animal oils or fats, we can cite, among others, sperm-whale oil,dolphin oil, whale oil, seal oil, sardine oil, herring oil, shark(dog-fish) oil, cod liver oil, neatsfoot oil, as well as beef, pork,horse, mutton tallow (marrow).

Animal or Vegetable Oil Compounds

We can also use compounds of animal or vegetable oils such as squaleneextracted from non-saponifiable fats of vegetable oils (olive oil,peanut oil, rapeseed oil, corn germ oil, cottonseed oil, linseed oil,wheat germ oil, rice bran oil) or squalene contained in massive amountsin shark (dog-fish) oil.

These animal or vegetable fats and oils, as well as their derivatives,can undergo a prior treatment intended to make them on the one hand morereactive or on the other hand less reactive. The invention relates toboth an isolated reagent and a reaction mixture comprising two or morecomponents. These reaction mixtures can include equivalent proportionsof each compound; or, certain compounds can be the primary compounds.

Hydrocarbons

As unsaturated hydrocarbons, we can cite, alone or in a mixture, and asnon-limitative examples, an alcene, for example one or several terpenichydrocarbons, that is to say, one or several polymers of isoprene, orone or several polymers of isobutene, of styrene, of ethylene, ofbutadiene, of isoprene, of propene, or one or several copolymers ofthese alcenes.

As saturated hydrocarbons, we can cite, among others, the alcanes, forexample ethane, propane.

Saturated and/or Unsaturated Esters

As for esters of saturated and/or unsaturated fatty acids, we can usesuch acids either alone or as a mixture, and by way of non-limitativeexamples, one or several esters obtained by esterification between amonoalcohol and/or polyol and at least one saturated and/or unsaturatedfatty acid; waxes; butters, phospholipids; spingolipids; glucolipids.

Saturated and/or Unsaturated Acids

As unsaturated fatty acids, we can use, either alone or in a mixture,and as non-limitative examples, one or several saturated acids such ascaprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid,arachidic acid, behenic acid, lignoceric acid, cerotic acid, one orseveral monounsaturated fatty acids such as oleic acid, palmitoleicacid, myristic acid, petroselenic acid, erucic acid; one or severalpolyunsaturated fatty acids such as for example linoleic acid, alpha andgamma linolenic acids, arachidonic acid; 5c,8c,11c,14c-eicosapentaenoicacid (EPA), 4c,7c,10c,13c,16c,19c-docosahexaenoic acid (DHA), one orseveral acids comprising conjugated dienes or conjugated trienes such aslicanic acid, isomers of linoleic and linolenic acids; one or severalacids comprising one or several hydroxyl groups such as ricinoleic acid.

Alcohols

As alcohols, we can mention, among others, glycerol, sorbitol, sucrose,mannitol, xylitol, neopentylglycol, pentaerythritol, saccharose,galactose, glucose, maltose, maltotriose, fructose, maltitol, lactitol,lactose, ribose, mellibiose, cellobiose, gentiobiose, altrose, gulose,polyalkyleneglycols, polyglycerols, polyphenols, alkylpolyglucosides,polyglucosides, glycol, pentaerythritol, 1,2-ethanediol, 1,4-butanediol;1,6-hexanediol, aminoalcohols (for example, diethanol amine (DEA),triethanol amine (TEA), 3-amino-1,2-propanediol), epoxyalcohols,saturated or unsaturated fatty alcohols (for example, myristyl alcohol,oleyl alcohol, lauryl alcohol), linear or branched alcohols, vitamins(for example, tocopherol, ascorbic acid, retinol), sterols (includingphytosterols), hemiacetals (for example, 1-ethoxy-1-ethanol),aminoalcohols (for example, 2-2′-aminoethoxy ethanol), epoxyalcohols(for example, 2-3-epoxy-1-propanol), propanol, ethanol, methanol,tetradecyl alcohol and their analogs.

The alcohols as well as their derivatives can undergo a prior treatmentintended to make them more reactive or, on the contrary, less reactive,such as for example: hydrogenation, hydroxylation, epoxydation,phosphitation, sulfonation.

Epoxides

As epoxydes, we can use, alone or in a mixture, and as non-limitativeexamples, vemolic acid, coronaric acid; 1,2-epoxy-9-decene,3-4-epoxy-1-butene, 2-3-epoxy-1-propanol, fatty esters obtained byesterification between 2-3-epoxy-1-propanol and a fatty acid (forexample, Cardura E10®).

Amino Alcohols

As amino alcohols, we can use, alone or in a mixture, and asnon-limitative examples, monoethanol amine (MEA), diethanol amine (DEA),triethanol amine (TEA), 3-amino-1,2-propanediol, 1-amino-2-propanol;2-2′-aminoethoxy ethanol.

Amines

As amines, we can mention, among others, ammonia, primary, secondary andtertiary alkyl amines (for example, methyl amine, dimethyl amine,trimethyl amine, diethyl amine), fatty amines (for example, oleicamines, coconut alkyl amines), amino alcohols (for example, monoethanolamine (MEA), diethanol amine (DEA), triethanol amine (TEA),3-amino-1,2-propanediol, 1-amino-2-propanol), ethoxylated amines(2-2′-aminoethoxy ethanol, amino-1-methoxy-3-propane).

All these amines can be saturated or nonsaturated, linear or branched.

Catalysts

Among the catalysts or additives, there shall be, as non-limitativeexamples, the common acid catalysts (para toluene sulfonic acid,sulfuric acid, phosphoric acid, perchloric acid, etc.), the common basiccatalysts (soda, potash, alcoholate of alkaline metals and ofalkaline-earth metals, sodium acetate, triethyl amines, pyridinederivatives, etc.), acid and/or basic resins of the Amberlite™,Amberlyst™, Purolite™, Dowex™, Lewatit™ types, zeolithes and enzymes,carbon blacks, and activated carbon fibers.

The invention will be better understood upon reading the followingdescription and the non-limitative examples given below.

EXAMPLES

The examples given below highlight the value of the invention and willallow any person skilled in the art to easily extrapolate to otherdimensions and/or geometries without departing from the true scope andspirits of the invention in its broader aspects.

Additionally, the following examples, which are given solely forpurposes of description and in no way of limitation, illustrate thevalue of the invention. These examples aim to demonstrate that theintermittent dielectric heating process is low-in-cost and permitsheating reaction volumes on an industrial scale while still benefitingfrom the advantages of this technology.

I. Volumes Exposed to Electromagnetic Waves

The tests were conducted on the laboratory and on industrial scale usingtwo (2) generators:

-   -   one (1) 6 kW magnetron generator operating at the 2450 MHz        frequency for the laboratory treatments

one (1) 60 kW magnetron generator operating at the 915 MHz frequency forthe industrial treatments Number of D (mm) H (mm) Unit Vexp reactorsTotal Vexp Pilot 30 45 32 mL 1 32 mL Industrial 100 124 1 L 4 4 L

wherein:

D=diameter of cylindrical reactors=2R

H=height of waveguide

Unit Vexp=volume exposed continually basis to waves for one reactor

Total Vexp=volume exposed continually to waves for both reactorsV(exposed to the field)=π*R ² *HII. Comparison between Conventional Heating and Intermittent DielectricHeatinga. Polyglycerol Synthesis

The tests are conducted at 260° C., in the presence of 2% sodium acetatein order to obtain a polyglycerol with a viscosity at 50° C. equal to3600 cP.

They make reference to Patent Application FR No 0108906. Total V ofReaction glycerol V ratio Time Intermittent Pilot 2,000 mL 1/62 3 hdielectric industrial 200 L 1/50 6 h 30 min heating ConventionalSchou >72 h heating

wherein:

Total V of glycerol=total volume of glycerol treated

V ratio=ratio between the volume exposed to waves and the total volumetreated

b. Synthesis of Polyglycerol Esters

Synthesis of Polyglycerol-6 Dioleate

The tests are carried out in the presence of 0.25% sodium acetate at230° C.

They make reference to Patent Application FR No 0108906. Total V ofReaction mixture V ratio time Intermittent 2000 mL 1/62 2 h 10 mindielectric heating Conventional 4 h 30 min heating

wherein:

Total V of mixture=total volume treated

V ratio=ratio between the volume exposed to waves and the total volumetreated

Synthesis of polyglycerol-2 Tristearate

The tests are carried out in the presence of 0.25% sodium acetate at260° C.

They make reference to Patent Application FR No 0108906. Total V ofReaction mixture V ratio time Intermittent 2000 mL 1/62 1 h 40 mindielectric heating Conventional 4 to 5 h heating

wherein:

Total V of mixture=total volume treated

V Ratio=ratio between the volume exposed to waves and the total volumetreated

c. Conclusion

Even if the entire reaction volume is not exposed to electromagneticwaves, the reaction times under intermittent dielectric heating areconsiderably lower than those obtained with conventional heating.

III. Comparison Between Intermittent Dielectric Heating and ContinuousDielectric Heating

a. Efficiency of Intermittent Dielectric Heating

The table below shows the efficiency of intermittent dielectric heatingcompared with continuous dielectric heating which is typically used.

The tests are carried out under the same conditions (composition ofreaction mixtures, temperatures, catalysts, etc.)

-   -   at the laboratory scale (use of a Synthewave 402) which uses        continuous dielectric heating    -   at the pilot scale, using a 2450 MHz generator that uses        intermittent dielectric heating    -   and at the production scale using a 915 MHz generator that uses        intermittent dielectric heating

The synthesis tested consists in manufacturing unsaturated fatty acidpolymers, unsaturated fatty acid esters, unsaturated hydrocarbons,unsaturated derivatives of these compounds, alone or in a mixture. PilotIndustrial Extrap- Extrap- Laboratory olated olated Mop MOi Mop MOi MopV_(treated) (mL) 25 2000 2000 200000 200000 V ratio 1/1 1/62 1/1 1/501/1 t_(reaction) (h) 2 h 15 min 2 h 15 min ≧2 h 15** 2 h 15 ≧2 h 15**

wherein:

Mop=continuous microwave heating

Extrapolated Mop=continuous microwave heating in the case of treatmentof 200 kg of product

Moi=intermittent microwave heating

V_(treated)=reaction volume treated

V ratio=ratio between the volume exposed to electromagnetic waves andthe total reaction volume

t_(reaction)=reaction time

**: Treating a large amount of products requires a reaction time greaterthan or equal to that for a lower amount. The reaction time is 2 h15 for25 mL of product. Thus, it can be asserted that the reaction time neededto treat 200 kg of the same mixture will be greater than or equal to 2h15.

This table shows that the reaction times are unchanged, whether oneworks on 25 mL, 2 kg, or 200 kg. However, in the case of pilot andindustrial tests (2 kg and 200 kg), the entire volume is not subjectedto dielectric heating:

-   -   laboratory test (continuous dielectric heating): the entire        volume is exposed to electromagnetic waves with Ratio=1/1    -   pilot test (intermittent dielectric heating): only 1/62 of the        volume is exposed to the field    -   industrial test (intermittent dielectric heating): only 1/50 of        the volume is exposed to the field

b. Lowering of Investment Costs

If we had to treat 200 liters of product using continuous dielectricheating, we would have to expose all 200 liters to the electromagneticwaves.

By working at the 2450 MHz frequency, the maximum volume exposed byapplicator is 32 mL. Here this configuration is not advantageous at all.In fact, we would need 6250 applicators.

By working at the 915 MHz frequency, the maximum volume exposed byapplicator is 1 L. We would then need 200 applicators.

For this invention, intermittent dielectric heating makes it possible touse only four (4) applicators, that is to say, 50 times less (a ratioconsistent with that given in the preceding table) for the sameproduction capacity.

We can compare the investment costs:

X=investment cost of a system with intermittent dielectric heating, 4channels, recycling

Y=investment cost of a system with continuous dielectric heating, 200channels, without recycling

Y=10*X

The investment cost would then be 10 times higher in the case of acontinuous dielectric heating compared with intermittent dielectricheating. This is essentially due to the cost of applicators, which ismuch higher than the rest of the system (buffer reactor, recycling pump,etc.).

1. A heat treatment process in a chemical synthesis, of the dielectrictype, characterized in that said dielectric heating is carried outintermittently, that is to say, the reagent or reagents is/are subjectedto electromagnetic waves intermittently, in combination with a recyclingsystem.
 2. A process as claimed in claim 1 wherein the electromagneticwaves are selected in the frequencies ranging between 300 GHz and 3 MHz.3. A process as claimed in claim 2 wherein the frequencies are selectedfrom among: MW frequencies and HF Those microwave frequencies (MW) thatrange from about 300 MHz to about 30 GHz, preferably standing at 915 MHz(authorized frequency with a tolerance of 1.4%) or at 2.45 GHz(authorized frequency with a tolerance of 2%). Those high frequencies(HF) that range from about 3 MHz to about 300 MHz, preferably standingat 13.56 MHz (authorized frequency with a tolerance of 0.05%) or at27.12 MHz (authorized frequency with a tolerance of 0.6%).
 4. A processas claimed in claim 1, wherein the entire reaction volume is notcontinuously exposed to dielectric waves but wherein all reactionmixture molecules are intermittently subjected to the field.
 5. Aprocess as claimed in claim 1, wherein the reagent(s) can be selectedfrom among those products that hardly absorb the electromagnetic wavesor those products that are highly absorbent of said waves or a mixtureof both, whether or not enhanced with one or several hardly or highlyabsorbent catalysts or additives and/or process gas.
 6. A process asclaimed in claim 5 wherein the reagent(s) is/are selected from among:vegetable oils rapeseed oil, sunflower oil, peanut oil, olive oil,walnut oil, corn oil, soy oil, linseed oil, safflower oil, apricotkernel oil, sweet almond oil, hemp oil, grassed oil, copra oil, palmoil, cottonseed oil, Babes oil, jujube oil, sesame oil, argon oil,milk-thistle oil, gourds oil, raspberry oil, Carnage oil, enema oil,poppies oil, Brazilnut oil, castor oil, dehydrated castor oil, hazelnutoil, wheat germ oil, borage oil, oenothera oil, Tung oil, or tall oil.animal fats or oils sperm-whale oil, dolphin oil, whale oil, seal oil,sardine oil, herring oil, shark (dog-fish) oil, cod-liver oil, neatsfootoil, as well as beef, pork, horse, mutton tallow (marrow). compounds ofanimal or vegetable oils squalene extracted from non-saponifiable fatsof vegetable oils (olive oil, peanut oil, rapeseed oil, corn germ oil,cottonseed oil, linseed oil, wheat germ oil, rice bran oil) or squalenecontained in large amounts in shark (dog-fish) oil. hydrocarbonsunsaturated: alone or in a mixture, an alcene, for example one orseveral terpenic hydrocarbons, that is to say, one or several polymersof isoprene, or one or several polymers of isobutene, of styrene, ofethylene, of butadiene, of isoprene, of propene, or one or severalcopolymers of these alcenes. saturated: alcanes, for example ethane,propane. saturated and/or unsaturated esters alone or in a mixture, oneor several esters obtained by esterification between a monoalcoholand/or polyol and at least one saturated and/or unsaturated fatty acid;waxes; butters, phospholipids; spingolipids; glucolipids. saturatedand/or unsaturated acids alone or in a mixture, one or several saturatedacids such as caprylic acid, lauric acid, myristic acid, palmitic acid,stearic acid, arachidic acid, behenic acid, lignoceric acid, ceroticacid, one or several monounsaturated fatty acids such as oleic acid,palmitoleic acid, myristic acid, petroselenic acid, erucic acid; one orseveral polyunsaturated fatty acids such as for example linoleic acid,alpha and gamma linolenic acids, arachidonic acid; 5c,8c, 11 c,14c-eicosapentaenoic acid (EPA), 4c,7c, 10c, 13c, 16c,19c-docosahexaenoic acid (DHA), one or several acids comprisingconjugated dienes or conjugated trienes such as licanic acid, isomers oflinoleic and linolenic acids; one or several acids comprising one orseveral hydroxyl groups such as ricinoleic acid. alcohols glycerol,sorbitol, sucrose, mannitol, xylitol, neopentylglycol, pentaerythritol,saccharose, galactose, glucose, maltose, maltotriose, fructose,maltitol, lactitol, lactose, ribose, mellibiose, cellobiose,gentiobiose, altrose, gulose, polyalkyleneglycols, polyglycerols,polyphenols, alkylpolyglucosides, polyglucosides, glycol,pentaerythritol, 1,2-ethanediol, 1,4-butanediol; 1,6-hexanediol,aminoalcohols (for example, diethanol amine (DEA), triethanol amine(TEA), 3-amino-1,2-propanediol), epoxyalcohols, saturated or unsaturatedfatty alcohols (for example, myristyl alcohol, oleyl alcohol, laurylalcohol), linear or branched alcohols, vitamins (for example,tocopherol, ascorbic acid, retinol), sterols (including phytosterols),hemiacetals (for example, 1-ethoxy-1-ethanol), aminoalcohols (forexample, 2-2′-aminoethoxy ethanol), epoxyalcohols (for example,2-3-epoxy-1-propanol), propanol, ethanol, methanol, tetradecyl alcoholand their analogs. epoxides alone or in a mixture, vernolic acid,coronaric acid, 1,2-epoxy-9-decene, 3-4-epoxy-1-butene,2-3-epoxy-1-propanol, fatty esters obtained by esterification between2-3-epoxy-1-propanol and a fatty acid (for example, Cardura E10®)).amino alcohols alone or in a mixture, monoethanol amine (MEA), diethanolamine (DEA), triethanol amine (TEA), 3-amino-1,2-propanediol,1-amino-2-propanol; 2-2′-aminoethoxy ethanol. amines ammonia, primary,secondary and tertiary alkyl amines (for example, methyl amine, dimethylamine, trimethyl amine, diethyl amine), fatty amines (for example, oleicamines, coconut alkyl amines), amino alcohols (for example, monoethanolamine (MEA), diethanol amine (DEA), triethanol amine (TEA),3-amino-1,2-propanediol, 1-amino-2-propanol), ethoxylated amines(2-2′-aminoethoxy ethanol, amino-1-methoxy-3-propane), which amines canbe saturated or unsaturated, linear or branched.
 7. A process as claimedin claim 6, wherein the animal or vegetable fats and oils, as well astheir derivatives, can undergo a prior treatment intended to make themon the one hand more reactive or on the other hand less reactive (bothan isolated reagent and a reaction mixture comprising two or severalcompounds, which reaction mixtures can comprise equivalent proportionsof each compound, or some compounds can be majority compounds).
 8. Aprocess as claimed in claim 6, wherein the alcohols as well as theirderivatives can undergo a prior treatment intended to make them on theone hand more reactive or on the other hand less reactive, such as forexample hydrogenation, hydroxylation, epoxidation, phosphitation,sulfonation.
 9. A process as claimed in claim 1, wherein it uses ascatalysts or additives: catalysts the common acid catalysts (paratoluene sulfonic acid, sulfuric acid, phosphoric acid, perchloric acid,etc.), the common basic catalysts (soda, potash, alcoholate of alkalinemetals and of alkaline-earth metals, sodium acetate, triethyl amines,pyridine derivatives, etc.), acid and/or basic resins of the Amberlite™,Amberlyst™, Purolite™, Dowex™, Lewatit™ types, zeolithes and enzymes,carbon blacks, and activated carbon fibers.
 10. A process as claimed inclaim 1, wherein the volume exposed to electromagnetic waves is with:one (1) 6 kW magnetron generator operating at the 2450 MHz frequency forthe laboratory treatments one (1) 60 kW magnetron generator operating atthe 915 MHz frequency for the industrial treatments Number of D (mm) H(mm) Unit Vexp reactors Total Vexp Pilot 30 45 32 mL 1 32 mL Industrial100 124 1 L 4 4 L

wherein: D=diameter of cylindrical reactors=2R H=height of waveguideUnit Vexp=volume exposed to waves on a continuous basis for one reactorTotal Vexp=volume exposed to waves on a continuous basis for bothreactorsV(exposed to the field)=π*R ² *H
 11. A device for the implementation ofthe process as claimed in claim 1, wherein it comprises or consists of:A) pumps reactors subjected to the electromagnetic field a dielectricsystem: chimney applicators, generator waveguides, iris, short-circuitpiston, cooling systems buffer reactors tanks a gas circuit, preferablyfor an inert gas such as nitrogen condensers measuring devices and inparticular B) pumps The pump(s) is/are of the variable flow type. It canbe a feeder dosing pump and/or a recycling pump and/or a vacuum pump.The outflow of the recycling pump influences the time required for amolecule to transit under the waves. The pumps can be selected, forpurpose of indication, from among vane pumps or piston pumps. one orseveral reactors subjected to electromagnetic waves a) The reactorssubjected to the electromagnetic field do not absorb waves (pyrex,quartz, etc.). b) They are typically cylindrical in shape. c) They arepositioned inside the applicators. a dielectric system: energyapplicators, chimneys, waveguides, generator, iris, and short-circuitpiston, cooling systems. a) The applicators are formed by singlemodecavities that resonate at the transmission frequency according to aradiation in the direction of the waveguide. b) The chimneys preventwave leakage to the outside of the waveguide. They are preferably of aconical cylindrical shape, as indicated in Application FR No 0108906filed by this Applicant for limiting the presence of electric arcs. c)The waveguide(s) carries/carry the electromagnetic waves. Each waveguidecan be subdivided into two—and only two—waveguides. d) The generatorsused are microwave or high-frequency generators. e) The microwave (MW)frequencies range from about 300 MHz to about 30 GHz, preferablystanding at 915 MHz (authorized frequency with a tolerance of 1.4%) orat 2.45 GHz (authorized frequency with a tolerance of 2%). f) The highfrequencies (HF) range from about 3 MHz to about 300 MHz, preferablystanding at 13.56 MHz (authorized frequency with a tolerance of 0.05%)or at 27.12 MHz (authorized frequency with a tolerance of 0.6%). g) Thegenerators are outfitted with a safety feature that allows the incidentwaves to pass through and that diverts the reflected waves to a waterload in which the waves are absorbed. h) These generators also requirethe use of iris, of a shortcircuit piston in order to decrease thereflected power and to promote absorption of the generator-transmittedpower by the reaction mixture. i) The system is outfitted with coolingsystems in order to avoid any overheating. buffer reactors The bufferreactors permit treating a larger amount of reaction mixture. tanks Thesystem is outfitted with one or several feeder tank(s), receivertank(s), filtration tank(s). gas circuits The heat treatments arecarried out under a normal atmosphere, or an oxygen-rich atmosphere or,preferably, an inert atmosphere. measuring devices The system isoutfitted with measuring devices such as manometers, thermocouples,flowmeters.
 12. A device as claimed in claim 11, wherein the process canbe used in dynamics or in continuum.
 13. A device as claimed in claims11 or 12, wherein it uses as energy applicator: type of energyapplicators As regards high frequency applicators, they consist mainlyin: applicators of the capacitive type formed by two condenser armaturesbetween which the generator's high-frequency voltage is applied. Theyare used for the heat treatment of materials whose volume constitutes aparallelepiped, one side of which is sufficiently thick (>10 mm).applicators with rods for planar materials. These applicators are madeup of tubular or rod-shaped electrodes. They are used for the heattreatment of materials whose volume constitutes a parallelepiped, oneside of which is insufficiently thick (<10 mm). applicators for filiformmaterials, formed by loops. As regards microwave applicators, we cancite: the localized-field applicators: singlemode cavity thediffuse-field applicators: multimode cavity the near-field applicators:waveguide with radiating antennas
 14. A device as claimed in claim 11,wherein: The “singlemode” system (localized field) which is formed bysinglemode cavities resonating at the transmission frequency accordingto a radiation in the direction of the waveguide, is preferable to the“multimode” (diffuse field). The applicator is outfitted with regularcylindrical chimneys. The device includes good venting with humid air orwith some other comparable gas as regards its dielectric constants (forexample, sulfur hexafluoride SF6 under 1 bar) or chimneys with speciallyadapted shapes so as to eliminate static electricity formed on theoutside wall of the reactor.
 15. A device as claimed in claim 11,wherein a specific chimney geometry is used, in particular a conicalchimney.
 16. A device as claimed in claim 11, wherein the reactor istypically cylindrical in shape, and its diameter may not exceed thewidth of the waveguide.
 17. A device as claimed in claim 11, wherein inthe case of singlemode microwave applicators, under 2450 MHz, thewaveguide width recommended in order to remain in the TE 0.1 (TransverseElectric) mode stands between about 70 and 100 mm, and more specificallyat 90 mm.
 18. A device as claimed in claim 11, wherein in the case ofsinglemode microwave applicators, under 915 MHz, the waveguide widthrecommended to remain in the TE 0.1 (Transverse Electric) mode is about250 mm.
 19. A device as claimed in claim 11, wherein the dielectricsystem comprises applicators, chimneys, waveguides, a generator, iris, ashortcircuit piston, cooling systems, as follows: The applicators areformed by singlemode cavities that resonate at the transmissionfrequency according to a radiation in the direction of the waveguide.The chimneys prevent wave leakage to the outside of the waveguide. Theyare preferably of a conical cylindrical shape, as indicated in PatentApplication FR No 0108906 filed by this Applicant for limiting thepresence of electric arcs. The waveguide(s) carries/carry theelectromagnetic waves. Each waveguide can be subdivided into two—andonly two—waveguides. The device also uses iris, short-circuit piston inorder to lower the reflected power and to promote absorption of thegenerated-transmitted power by the reaction mixture.
 20. A Process asclaimed in claim 1, characterized in that the heat treatments arecarried out under a normal atmosphere, or an oxygen-rich atmosphere, orpreferably under an inert atmosphere.
 21. Applications of the process asclaimed in claim 1 in all “heat applications” chemical synthesesinvolving a heat treatment and the use of a single reagent, or a mixtureof reagents, in variable proportions, with or without catalysts, with orwithout process gas.
 22. Applications as claimed in claim 21, wherein as“heat applications” we can cite, as non-limitative examples, suchreactions as esterification, transesterification, epoxidation,sulfatation, phosphitation, hydrogenation, peroxidation, isomerization,dehydration, quaternization, amidation, polymerization,polycondensation, and all the common treatments such as decolorizing,deodorizing, and the other systems for eliminating volatile compounds.23. Applications of the process as claimed in claim 1 to all“lipochemistry” reactions.
 24. Applications of the process as claimed inclaim 1 for manufacturing polymers of unsaturated fatty acids, ofunsaturated fatty acid esters, of unsaturated hydrocarbons or ofderivatives of these products using intermittent dielectric heatingunder microwaves.
 25. Applications of the process as claimed in claim 1specific to the synthesis of: polyglycerol polyglycerol esterspolyglycerol-6 dioleate polyglycerol-2 tristearate